This unusual creation, a relative of the jellyfish, common in subtropical and tropical latitudes of the oceans, in Europe can be found in the western part of the Mediterranean Sea and on the west coast. Key findings of the type known by individuals, cast ashore on the coast of the UK and Ireland.

Velella (lat. Velella velella) - the representative of the colonial hydroids, oceanic pelagic species, the only member of the genus.

Velella is not an independent body, and a colony of hydroids that have different shapes and specialization.

Inside the colony formed flat air-filled chamber of chitin, which is covered with a mantle. It was she who maintains the entire colony on the surface of the water. The column base is an oval fortified chitin structures. A characteristic feature is a kind of thin semi-circular blade, located on a diagonal from the top of the air chamber. Above the base rises a sail that is asymmetrical and is curved in the shape of letter S. With this blade the animal has been called (from the Latin. «Velum» - sail). This outgrowth allows animals to move around the surface of the water is not in a straight line, and at a certain angle to the wind, occasionally turning 180 degrees. Colony size can reach 10 centimeters (typically about 7 cm.). Threadlike tentacles, rather short, hanging from the air chamber. Their number varies from 8 or more.

There is a pronounced central large polyp, which specializes in catching and digesting food. It is surrounded by polyps, specializing in nutrition and reproduction, and polyps, specializing in protection function.